3D Electronic Circuit Manufacturing via Conformal Mask Plating
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Solution Overview
Problem
Existing methods for manufacturing three-dimensional electronic circuits, such as antennas, face challenges in achieving sufficient thickness and low electrical resistance for soldering, as current techniques result in thin metal layers that are too thin for soldering and have high electrical resistance, especially for ultra-high frequency applications like GPS receivers.
Innovation Solution
A method involving the use of a conformal mask with apertures that match the non-planar shape of a three-dimensional substrate, allowing selective deposition of a conductive material followed by electroplating or electroless plating to achieve a thicker, solderable electrically conductive film, with an environmentally protective coating to enable soldering while maintaining low resistance contacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If physical vapor deposition (PVD) or chemical vapor deposition (CVD) is used to deposit metal through shadow masks, then the deposition process can be performed, but the resulting metal layer is too thin (about 1.2 μm) for soldering and has high electrical resistance
Solution Approach 1:
A seed layer is deposited first through the shadow mask to define the pattern, then electroplating is performed to build up additional thickness. This preliminary deposition of a thin conductive layer enables subsequent plating to achieve solderable thickness while maintaining the pattern definition from the initial thin film deposition.
Solution Approach 2:
The invention changes the deposition method from single-step PVD/CVD to a two-step process combining thin film deposition with electroplating. This parameter change in the manufacturing process enables achieving both the precision of thin film deposition and the thickness required for soldering, resulting in metal layers 4-100 μm thick with low electrical resistance.
2Adaptability or versatility
If conformal masks are used to deposit metal on three-dimensional substrates, then the mask can conform to non-planar surfaces, but the deposited metal layer remains too thin for soldering applications
Solution Approach 1:
The conformal mask is first used to deposit a thin seed layer that conforms to the three-dimensional substrate surface, establishing the pattern. Then electroplating is applied to build up additional thickness on top of this conformal seed layer, achieving both surface conformity and sufficient thickness for soldering.
Solution Approach 2:
The invention uses a composite approach combining two different deposition techniques: thin film deposition (PVD/CVD) through the conformal mask to create the initial patterned layer, followed by electroplating to add thickness. This composite process achieves both conformality to 3D surfaces and solderable metal thickness.
3Adaptability or versatility
If metallic inks are omnidirectional printed directly on flexible surfaces, then the circuits can be printed on complex surfaces, but the electrical resistivity is several times larger than metallic bulk resistivity
Solution Approach 1:
The invention replaces the mechanical printing process (omnidirectional printing of metallic inks) with a vapor deposition process through shadow masks followed by electroplating. This substitution eliminates the high resistivity associated with printed metallic inks while maintaining the ability to deposit on flexible and complex surfaces, achieving bulk-metal-level electrical conductivity.
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
The method enables the fabrication of solderable three-dimensional electronic circuits with conductive films that are twice as thick as the skin depth of GPS signals, achieving electrical conductivity comparable to conventional thin films and allowing for reliable connections with other electronic components.
Implementation Method 1
The materials may be conductors, such as metals, and the deposition may be by chemical vapor deposition (CVD) or by physical vapor deposition (PVD), such as sputtering or evaporative deposition
Implementation Method 2
The materials may be conductors, such as metals, and the deposition may be by chemical vapor deposition (CVD) or by physical vapor deposition (PVD)
Implementation Method 3
Plating may be performed by electroplating or electroless plating
Implementation Method 4
Electron beam evaporation was then used to deposit copper, through apertures in the mask, onto the surface of the paraboloid
Data Source
AI summary
An electronic circuit is made by selectively depositing an electrically conductive material seed layer conformally upon a three-dimensional substrate via the plurality of apertures of a three-dimensional mask. The substrate is then plated with more of the same electrically conductive material, or a different electrically conductive material, on the seed layer. In the case of electroplating, a nonconductive support structure is incorporated into a conductive clamp for making electrical connection to the seed layer. An environmentally protective layer may be deposited upon the electrically conductive material to such an extent that the electronic circuit remains solderable. The three-dimensional mask may be fabricated by an additive manufacturing technique.