Silicon Watch Components With Multilevel DRIE to Avoid Brittle Assembly
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Solution Overview
Problem
The assembly of silicon watch components using the press-fit method is unsuitable for industrial production due to high breakage rates, as silicon is a brittle material, making it difficult to use the traditional 'driving' technique for assembling complex components like anchors and other watch parts.
Innovation Solution
A method involving deep reactive ion etching (DRIE) with primary and secondary etching masks on both sides of a monolithic silicon wafer to form multilevel components, ensuring alignment and eliminating the need for laborious assembly steps by creating a monolithic silicon component with defined levels and edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the press-fit assembly method is used for silicon components, then the assembly of complex components can be achieved, but the breakage rate increases significantly due to silicon's brittle nature
Solution Approach 1:
The patent merges multiple separate components into a single monolithic silicon component by using depth-selective etching to create internally separated levels within one continuous silicon structure. This eliminates the need for press-fit assembly of multiple pieces, thereby avoiding breakage while achieving complex multilevel geometry.
Solution Approach 2:
The patent segments the monolithic silicon component into multiple levels or zones at different depths, each with distinct geometries formed by selective etching. This internal segmentation allows complex functionality without requiring physical assembly of separate parts, maintaining structural integrity.
2Adaptability or versatility
If multiple separate elements are assembled to create complex components, then the required functionality can be achieved, but the manufacturing process becomes laborious and unsuitable for industrial production
Solution Approach 1:
The patent combines multiple functional elements into a single monolithic silicon component that is manufactured in one integrated process using depth-selective etching. This eliminates multiple assembly steps and enables high-volume industrial production while maintaining complex multilevel functionality.
Solution Approach 2:
The patent performs preliminary structuring of the silicon wafer by creating depth-selective etching masks and defining etch stop layers before the actual etching process. This preliminary preparation enables the subsequent formation of complex multilevel structures in a single batch process, greatly improving manufacturing efficiency.
3Manufacturing precision
If deep ion reactive etching is used to create complex geometries, then precise component shapes can be achieved, but the process requires multiple etching steps from both sides of the wafer
Solution Approach 1:
The patent introduces depth as a selective dimension by using depth-selective etching with etch stop layers at specific depths. This allows the etching process to reach different depths in different regions of the wafer, creating complex multilevel structures through a systematic approach that manages process complexity.
Solution Approach 2:
The patent uses etch stop layers as intermediary elements that control the depth of etching. These stop layers act as mediators between the etching process and the final geometry, allowing precise depth control and enabling the formation of complex structures through manageable sequential steps.
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 process allows for the rapid and efficient production of complex silicon watch components with reduced breakage, enabling large-scale manufacturing of components such as anchors, wheels, plates, and needles by ensuring precise etching and alignment without the need for separate assembly steps.
Implementation Method 1
Create at least one stop layer comprising a parylene layer on the first etched side of the wafer
Implementation Method 2
Etch the wafer through said at least one opening of the first primary etching mask to form the edges of a first level of the component
Data Source
Figure 1~2
Figure 3a~3b5
Figure 3c~3e4
AI summary
The present invention relates to a method for manufacturing at least one watch component, in which, on a first side of a monolithic silicon wafer (100), a first primary etching mask (200) is made and then the wafer (100) is etched through the first mask (200) to form the edges of a first level of the component; at least one stop layer (400) is made on the first etched side (101) of the wafer (100); on the second side of the wafer (102) opposite to the first side (101), a second secondary etching mask (300) is made and then the wafer (100) is etched through this second mask (300) to form the edges of a second level of the component, the secondary etching reaching at least locally the stop layer.