Structured Nickel-Titanium Layer Production via Segmented Etching
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Solution Overview
Problem
Current methods for producing structured nickel-titanium metal layers face challenges such as low etching rates, material redeposition, and surface defects, which hinder the production of high-strength, biocompatible implants like stents and embolism filters.
Innovation Solution
A method combining wet-chemical etching of the first sacrificial layer with dry-etching of the second sacrificial layer, followed by sputtering of the nickel-titanium alloy, ensures a smooth surface and efficient creation of structured metal layers with high breaking strength, minimizing undercutting and hydrogen introduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wet-chemical etching is used to structure the nickel-titanium layer, then the etching process is simple and isotropic, but undercutting occurs and edge structure is negatively influenced
Solution Approach 1:
The patent divides the etching process into two separate stages performed on different sacrificial layers: wet-chemical etching is applied to the first sacrificial layer to create through-holes, while dry etching is applied to the second sacrificial layer to define precise edge structures. This segmentation allows each etching method to be optimized for its specific function, resolving the contradiction between process simplicity and edge accuracy.
2Manufacturing precision
If dry etching is used to structure the nickel-titanium layer, then edge structures are produced cleanly without undercutting, but the etching rate is low and material redeposition occurs
Solution Approach 1:
The patent segments the etching tasks between two different sacrificial layers: the first sacrificial layer is etched using wet-chemical methods which provide high etching rates for creating through-holes, while the second sacrificial layer is etched using dry etching methods which provide clean edge structures. This segmentation allows the system to achieve both high productivity and high precision without the limitations of using a single etching method.
3Device complexity
If a single sacrificial layer is used, then the process is simple, but both wet-chemical and dry etching cannot be optimally combined
Solution Approach 1:
The patent introduces a segmented sacrificial layer system with at least two distinct sacrificial layers: a first sacrificial layer that is removed by wet-chemical etching to create through-holes, and a second sacrificial layer that is removed by dry etching to define precise edge structures. This segmentation of the sacrificial layer system enables the optimal combination of different etching methods, resolving the contradiction between process simplicity and manufacturing precision.
4Productivity
If chemical etching is used, then the process is fast, but hydrogen is introduced into the nickel-titanium alloy affecting shape memory properties
Solution Approach 1:
The patent segments the etching process so that wet-chemical etching is applied only to the first sacrificial layer where speed is prioritized, while dry etching is applied to the second sacrificial layer that directly contacts the nickel-titanium alloy. This segmentation prevents hydrogen introduction into the alloy while maintaining high etching speeds for the sacrificial layers, thus preserving the shape memory properties.
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 rapid, cost-effective production of high-strength, biocompatible structured metal layers with improved edge accuracy and reduced material defects, suitable for medical implants like stents and embolism filters.
Implementation Method 1
it is provided that the first sacrificial layer, which is further away from the metal layer to be deposited, is subjected to the wet-chemical etching process
Implementation Method 2
the second sacrificial layer facing the metal layer to be deposited is subjected to a dry-etching process
Implementation Method 3
The metal layer is applied in a thickness of approx. 3 µm directly as a structured metal layer or as a structured metal foil to the remaining residue of the upper sacrificial layer 2
Data Source
Figure 1~7
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Figure 12~17
AI summary
The invention relates to a method for the production of a structured metal layer (7) made of an alloy containing titanium and nickel, wherein the method consists of the following steps: - a sacrificial layer compound (3) is used, which comprises a second sacrificial layer (2) applied on top of a first sacrificial layer (1); - one of the two sacrificial layers (1) is used to structure a wet chemical etching method in such a way that the sacrificial layer (1) is undercut; - a metal layer (7) of the above-mentioned alloy is directly or indirectly applied to the structured sacrificial layer compound (3). During this process, the first sacrificial layer (1), which is at a greater distance from the metal layer (7), is subjected to a wet chemical etching process, while the second sacrificial layer (2) adjoining the metal layer (7) is subjected to a dry etching process before the first sacrificial layer (1) is subjected to the wet chemical etching process, wherein it is provided with a structure that corresponds to the desired structure of the metal layer (7). The invention further relates to an object, particularly a stent or an implant, that comprises at least one metal layer (7) which is produced using the method in accordance with one of the above claims.