3D Electrical Circuit Formation Using Undercut Shadow Masking
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Solution Overview
Problem
Conventional 2D microfabrication techniques are costly, complex, and limited in producing three-dimensional (3D) electronic circuits with high feature resolution and precision, posing challenges for advanced miniature devices like multi-axis gyroscopes and microwave circuits.
Innovation Solution
The method involves additive manufacturing to form 3D structures with undercuts that create overhang deposition masks, allowing selective material deposition on 3D structures, enabling the formation of electrically isolated conductive traces without the need for traditional etching processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional 2D microfabrication techniques are used to produce 3D electronic circuits, then manufacturing capability is maintained, but manufacturing precision and feature resolution deteriorate
Solution Approach 1:
The patent transitions from conventional 2D microfabrication to 3D additive manufacturing, enabling the fabrication of three-dimensional electronic circuits with complex geometries including undercuts, overhangs, and multi-level structures. This dimensional change allows direct production of 3D circuits without requiring complex 2D process adaptations, thereby improving manufacturing precision for 3D features while maintaining ease of manufacture through established additive manufacturing technologies.
2Device complexity
If traditional etching processes are used to form conductive traces, then conductive patterns are created, but device complexity and processing steps increase
Solution Approach 1:
The patent extracts and eliminates the traditional etching process from the manufacturing sequence. Instead of depositing conductive material and then etching away unwanted portions, the method directly forms conductive traces through selective material deposition in 3D space, using the deposited material itself and surrounding structures as masks. This removes the harmful etching step entirely, reducing device complexity and processing steps while maintaining ease of manufacture for conductive trace formation.
Solution Approach 2:
The patent inverts the traditional subtractive manufacturing approach by using additive manufacturing. Instead of starting with a continuous conductive layer and removing material to create traces, the method directly deposits conductive material only where traces are needed. This inversion eliminates the need for photoresist coating, light exposure, and chemical etching, significantly reducing processing steps and device complexity.
3Manufacturing precision
If photoresist and light exposure methods are used for pattern formation, then conductive layouts are defined, but manufacturing precision is limited
Solution Approach 1:
The patent replaces the photochemical pattern formation system (photoresist coating, light exposure, development) with a direct mechanical/material deposition system. Conductive traces are formed by selectively depositing conductive material using techniques such as aerosol jet printing, electrostatic deposition, or directed energy deposition. This substitution eliminates the limitations of photoresist resolution and chemical development processes, achieving higher manufacturing precision for layout definition while reducing overall device complexity by removing multiple processing 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 approach enables the fabrication of 3D electronic circuits with precise feature resolution and reduced processing steps, overcoming limitations of conventional methods and facilitating the production of complex 3D devices like MEMS and microantennas.
Implementation Method 1
The undercut formed in the pedestal portion defines an upper level overhang configured to define a mask region on a corresponding portion of the lower level
Implementation Method 2
deposition of the selected material on the 3D structure
Implementation Method 3
deposition of the selected material on the 3D structure
Data Source
Figure 1
Figure 2
Figure 3A~3D
AI summary
Methods for forming electrical circuitries on three-dimensional (3D) structures and devices made using the methods. A method includes forming selectively shaped 3D structures using additive manufacturing. The method includes forming undercuts on upper-level pedestals of the 3D structures that effectively act as overhanging deposition masks for selectively preventing deposition of a selected material on a corresponding portions of lower levels. The method includes simultaneously forming and electrically isolating materials directionally deposited on the 3D structure.