Multilevel Silicon Micromechanical Parts Fabrication
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Solution Overview
Problem
Current techniques for manufacturing multilevel silicon micromechanical parts from a single silicon wafer are delicate and lack a simple, economical solution for precise assembly and linking of elements in watchmaking construction.
Innovation Solution
A method involving machining and precise structuring of elements on silicon wafers, followed by thermal oxidation to physically link them, using various positioning means and techniques like RIE for structuring and dry or wet oxidation processes, allows for the creation of multilevel silicon parts such as bearings and bridges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If current techniques are used to manufacture multilevel silicon micromechanical parts from a single silicon wafer, then the verticality of the blanks is sufficiently controlled, but the manufacturing process becomes very delicate and complex
Solution Approach 1:
The invention divides the manufacturing process into separate stages: first machining individual elements on separate wafers, then assembling them into multilevel structures. This segmentation simplifies each individual manufacturing step while achieving the overall complex multilevel structure through controlled assembly of simpler components.
2Manufacturing precision
If multilevel parts are manufactured from a single silicon wafer using current techniques, then verticality is controlled, but the process lacks simplicity and economic efficiency
Solution Approach 1:
The manufacturing process is segmented into independent stages where simple single-level elements are machined on separate wafers using conventional techniques, then assembled into multilevel structures. This approach maintains manufacturing simplicity at each stage while achieving complex final structures.
Solution Approach 2:
Individual elements are preliminarily machined and prepared on separate wafers before final assembly. This preliminary action allows each element to be manufactured using simple, well-established techniques, and the complexity is managed through the subsequent controlled assembly process.
3Manufacturing precision
If multilevel parts are manufactured from a single silicon wafer, then verticality is sufficiently controlled, but the process is not economical
Solution Approach 1:
The process segments manufacturing into independent stages using conventional, well-established techniques for each stage. This allows the use of existing, cost-effective manufacturing methods rather than requiring expensive new equipment or processes for multilevel fabrication.
Solution Approach 2:
The invention uses conventional machining techniques that are already proven and optimized for single-level elements. By copying these existing successful processes and applying them to separate wafers that are then assembled, the method achieves economic efficiency by leveraging established manufacturing capabilities.
4Adaptability or versatility
If elements are assembled to form multilevel parts, then complex micromechanical structures are obtained, but precise positioning and linking become difficult
Solution Approach 1:
The invention introduces intermediary elements such as bridges and positioning features that facilitate precise assembly. These intermediaries act as mediators between the separate elements, ensuring accurate positioning and secure linking while enabling the formation of complex multilevel structures.
Solution Approach 2:
The assembly process uses positioning means that create equipotential conditions for alignment, ensuring that elements are positioned with high precision relative to each other. This approach maintains manufacturing precision while enabling complex structural configurations.
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
Enables the efficient and cost-effective manufacturing of multilevel micromechanical parts with precise control over dimensions and assembly, suitable for watch movements, by structuring and linking elements from commercial silicon wafers.
Implementation Method 1
carrying out thermal oxidation to physically link the two elements together
Implementation Method 2
The step of oxidation of the interface between the wafers can be carried out by a dry process with dry oxygen, or by a wet process with steam
Data Source
AI summary
The process comprises the following steps: a) a first element (3) or a plurality of said first elements (3) is/are machined in a first silicon wafer (1) keeping said elements (3) joined together via material bridges (5); b) step a) is repeated with a second silicon wafer (2) in order to machine a second element (4), differing in shape from that of the first element (3), or a plurality of said second elements (4); c) the first and second elements (3, 4) or the first and second wafers (1, 2) are applied, face to face, with the aid of positioning means (6, 7); d) the assembly formed in step c) undergoes oxidation; and e) the parts (10) are separated from the wafers (1, 2). Micromechanical timepiece parts obtained according to the process.