Sub-Micron Metal Replication via Low-Temperature CVD
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Solution Overview
Problem
Current methods for fabricating high resolution, complex 3D parts in metals are limited by the inability to achieve sub-micron scale resolution due to challenges with surface phenomena and electrostatic behavior, and existing technologies like MEMS are restricted to few layers and modest resolution in real materials.
Innovation Solution
A high resolution additive manufacturing method combining micro-stereolithography with a low temperature chemical vapor deposition (CVD) process, where a stable material like nickel is deposited around a 3D polymer part, allowing for the dissolution of the polymer and replication of the structure at sub-micron scales, with the CVD process operating at atmospheric pressure and using nickel carbonyl with hydrogen sulfide as a catalyst.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If powder bed fusion processes are used to fabricate high resolution parts in metals, then complex 3D structures can be created, but resolution is limited to about 100 microns and cannot achieve sub-micron scale due to surface phenomena and electrostatic behavior
Solution Approach 1:
The patent uses a polymer replica as an intermediary object. Instead of directly fabricating metal parts at sub-micron scale (which is hindered by surface phenomena), the process creates a polymer replica first using micro-stereolithography, then uses chemical vapor deposition to transfer the structure to metal. This intermediary approach allows sub-micron resolution to be achieved in the polymer, which is then replicated in metal without being affected by the same surface phenomena that limit direct metal fabrication.
Solution Approach 2:
The patent employs a copying strategy where the 3D structure is first created in polymer using micro-stereolithography, then this polymer structure serves as a mold or template. Through chemical vapor deposition, the structure is copied into metal, preserving the sub-micron resolution achieved in the polymer phase. This copying approach bypasses the resolution limits of direct metal additive manufacturing.
2Manufacturing precision
If MEMS processes with photo-resist and optical pattern exposure are used, then high resolution can be achieved, but part complexity is limited to just a few layers typically six layers or less
Solution Approach 1:
The patent uses micro-stereolithography to preliminarily create the complete 3D polymer structure in a single continuous printing process, rather than building layer-by-layer with photo-resist exposure. This preliminary action allows complex multi-layer structures to be fabricated without the layer number limitations of MEMS processes, while maintaining high resolution through the optical precision of stereolithography.
3Manufacturing precision
If smaller powder grains are used in powder bed fusion to achieve higher resolution, then surface to volume ratio increases, but gravity becomes less important and behavior is dominated by electrostatics and other surface phenomena
Solution Approach 1:
The patent avoids directly manipulating small metal powder particles (which are subject to electrostatic dominance) by using a polymer intermediary. The polymer is deposited as a continuous material through stereolithography, avoiding powder handling issues. The metal structure is then formed by chemical vapor deposition onto the polymer template, bypassing the need to directly control small metal powder particles and their electrostatic behavior.
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 creation of true 3D structures at sub-micron scales in metals, overcoming limitations of existing technologies by achieving high resolution and complexity, with potential applications in CMOS sensor arrays and other sensor technologies.
Implementation Method 1
depositing the stable material at a process temperature of 100° C. or less
Implementation Method 2
The CVD process utilizes nickel from nickel carbonyl gas with hydrogen sulfide as a catalyst, thereby creating a nickel shell as the stable material
Implementation Method 3
removing the 3D polymer part by accessing the inside of the rigid shell through the sprue to allow dissolution of the 3D polymer part
Implementation Method 4
the removing of the 3D polymer part comprises ashing the 3D polymer part with a reactive gas. In one embodiment, the reactive gas comprises atomic oxygen
Data Source
AI summary
The present invention relates to a high resolution additive manufacturing method, including: creating a rigid shell of a stable material on all surfaces except for a sprue of a three dimensional (3D) polymer part using a chemical vapor deposition (CVD) process which includes: depositing the stable material at a process temperature of 100° C. or less, and operating at, or near, atmospheric pressure; and removing the 3D polymer part by accessing the inside of the rigid shell through the sprue to allow dissolution of the 3D polymer part, thereby leaving a replicated rigid shell of the stable material.