Nanoparticle Extrusion Across Microscopic Steps for Conductive Continuity
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Solution Overview
Problem
Current technologies face challenges in forming electrically conductive features that traverse microscopic steps on or in substrates using metallic nanoparticle compositions, particularly in achieving continuous and reliable connections across varying surface roughness and heights.
Innovation Solution
A method involving the continuous extrusion of metallic nanoparticle compositions from a capillary tube while displacing it relative to the substrate along specific trajectories, with varying pressures applied based on surface roughness, to form continuous extrudates that connect across step top and bottom portions, and a corresponding apparatus with a piston-cylinder assembly and regulated pneumatic system for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metallic nanoparticle composition is extruded continuously across a microscopic step, then continuous conductive feature is formed, but maintaining consistent extrusion pressure and flow rate becomes difficult due to varying surface roughness and height
Solution Approach 1:
The system dynamically adjusts the extrusion pressure in real-time based on the capillary tube's vertical position and the substrate surface topography. The pressure varies continuously as the capillary moves across different heights and surface roughness zones, allowing the extrusion rate to adapt to changing conditions while maintaining continuous material flow and feature continuity.
Solution Approach 2:
The system employs feedback control where the vertical position of the capillary tube relative to the substrate surface is continuously monitored, and this information feeds back to adjust the extrusion pressure. This closed-loop control ensures that pressure adjustments are made in response to actual surface conditions, maintaining both feature continuity and acceptable pressure control despite varying topography.
2Adaptability or versatility
If the capillary tube is displaced along a sloped trajectory to traverse the step, then the conductive feature can bridge the height difference, but the extrusion process becomes more complex requiring coordinated control of multiple degrees of freedom
Solution Approach 1:
The print head assembly serves multiple functions: it positions the capillary tube in three-dimensional space (x, y, z coordinates), controls the extrusion pressure, and manages the trajectory along sloped paths. This multi-functional design allows a single integrated system to handle both the geometric adaptation to surface variations and the material deposition, reducing the need for separate specialized components.
Solution Approach 2:
The system uses dynamic trajectory control where the capillary tube follows sloped paths that adapt to the substrate topography. The trajectory is not fixed but can be adjusted in real-time to match the surface profile, allowing the system to bridge height differences effectively while maintaining control over the deposition process.
3Reliability
If pressure is increased to ensure material flow across rough surfaces, then coverage is improved, but the risk of discontinuities and defects increases
Solution Approach 1:
The system changes the pressure parameter dynamically rather than maintaining a constant high pressure. By adjusting pressure in response to real-time conditions such as surface roughness and capillary position, the system achieves adequate coverage on rough surfaces while avoiding the excessive pressure that would cause defects and discontinuities. This parameter modulation allows optimization of both coverage and uniformity.
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 formation of reliable and continuous electrically conductive features traversing microscopic steps, even across significant height and surface roughness variations, with improved precision and efficiency.
Implementation Method 1
The pressure is varied in accordance with a surface roughness of a respective portion of the substrate underlying the capillary tube
Implementation Method 2
continuously extruding a metallic nanoparticle composition from a capillary tube
Data Source
AI summary
A method of forming an electrically conductive feature traversing a microscopic step on or in a substrate is disclosed. A metallic nanoparticle composition is continuously extruded from a capillary tube (nozzle) while displacing the capillary tube along a first portion of a trajectory from a first position (above a step-top portion) past an edge of the microscopic step to a second position to form a first extrudate. The composition is continuously extruded while displacing the nozzle along a sloped second portion of the trajectory from the second position to a third position (above a step-bottom portion) to form a second extrudate. The third position is at a lower height than the second position. The composition is continuously extruded while displacing the nozzle along a third portion of the trajectory from the third position to a fourth position (above the step-bottom portion). The feature includes the first, second, and third extrudates.