Multi-Level Metal Micro-Parts Nested Self-Assembly
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Solution Overview
Problem
Existing methods for manufacturing micro metal parts with multiple levels, such as those used in watchmaking, often result in parts with superimposed levels that are not nested or self-assembled, lacking the precision and structural integrity required for complex mechanical components.
Innovation Solution
A method involving photolithography and electroforming, where the second level grows within the space formed in the first metal layer, allowing for nested self-assembly, with the mold created using the LIGA process or a combination of deep etching and LIGA, ensuring intimate bonding and precise positioning of levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing LIGA-based methods are used to manufacture multi-level micro metal parts, then production capability is achieved, but the levels are not nested or self-assembled, resulting in reduced structural integrity and precision
Solution Approach 1:
The patent implements nesting by configuring the mold cavity such that the projection of upper levels is partially included in the projection of lower levels. The electroforming process deposits metal layers that grow vertically while maintaining nested spatial relationships, with each level partially contained within the projection of the level below it, creating self-assembled nested structures with enhanced structural integrity
Solution Approach 2:
The patent applies preliminary action by pre-configuring the mold cavity geometry before electroforming to define the nested spatial relationships. The mold is designed with specific cavity projections that guide the sequential deposition of metal layers into their final nested positions, ensuring precise self-assembly without requiring post-processing alignment
2Device complexity
If multiple separate metal layers are deposited planarly with bonding layers, then multi-level structure is achieved, but assembly between levels is lost and structural integrity is reduced
Solution Approach 1:
The patent merges the formation of multiple metal levels into a single integrated electroforming process rather than separate deposition steps. The mold cavity is configured to define all level geometries simultaneously, and the electroforming process deposits all metal layers in one continuous operation, creating inherent mechanical interlocking between levels without requiring separate bonding operations
Solution Approach 2:
The patent uses the mold cavity as an intermediary structure that defines the nested spatial relationships between levels. The cavity geometry acts as a template that guides metal deposition into precise nested positions, and the mold material itself becomes part of the final structure, providing mechanical interlocking that replaces the need for separate bonding layers
3Productivity
If photoresist layers are superimposed and metal is deposited in orifices, then multi-level parts are produced, but the levels are not nested and self-assembled
Solution Approach 1:
The patent transitions from planar superposition of photoresist layers to a three-dimensional nested cavity structure. Instead of depositing metal in separate planar orifices, the electroforming process deposits metal vertically into a unified three-dimensional cavity where levels are nested in the vertical dimension, achieving both productivity and precise nested positioning
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 production of three-dimensional metal micro-parts with multiple nested levels, providing enhanced precision and structural integrity, allowing for the creation of complex mechanical components like those in watchmaking with micrometric precision.
Implementation Method 1
depositing on a substrate a layer of 1 to 2000 μm of a photosensitive resin (photoresist); carry out through a mask irradiation by means of a synchrotron or by exposure to ultraviolet rays
Implementation Method 2
electroforming a metal in this cavity in order to obtain a metal micro part
Data Source
Figure 1~4
Figure 5A~5G
Figure 6A~6G
AI summary
The present invention relates to a method for manufacturing three-dimensional metallic micro-parts comprising at least two levels obtained by photolithography and electroforming. The second level of these micro-parts is nested and bonded to the first level by at least one through-hole formed in the first metallic layer of the first level, or by coating the second metallic layer of the second level with at least a portion of the contour of the first metallic layer of the first level, or both. Furthermore, the second level extends partially over the first level and into an area outside the vicinity of said first level, such that the contour of an orthogonal projection of the second level encompasses a portion of the contour of the first level. The two levels may be made of the same or different metals.