Conductive Metal Traces With Electrochemical Oxide Removal and Light Sintering
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Solution Overview
Problem
Existing methods for manufacturing biodegradable or bioresorbable electrically conductive metal traces face challenges such as limited scalability, resolution issues due to drop casting, insufficient conductivity, substrate damage, and high energy requirements, while maintaining thickness and substrate integrity.
Innovation Solution
A two-stage process involving electrochemical removal of the oxide layer followed by light-induced heat sintering is applied to metal particles deposited on a substrate, allowing for large-scale production of conductive metal traces with improved conductivity and strength without damaging the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser sintering is used to melt metal particles, then conductivity is improved, but substrate damage occurs and energy consumption increases
Solution Approach 1:
The patent changes the sintering parameters by using pulsed light with specific wavelength ranges (visible to near-infrared) and controlled pulse durations (microseconds to milliseconds). This allows selective heating of metal particles without excessive thermal diffusion to the substrate, achieving sintering at lower peak temperatures and reduced thermal damage compared to continuous laser sintering.
Solution Approach 2:
The patent employs pulsed light sintering where light is delivered in periodic pulses rather than continuous illumination. This periodic action allows heat to dissipate between pulses, preventing cumulative thermal damage to the substrate while still achieving sufficient energy accumulation for particle sintering during the pulse periods.
2Use of energy by moving object
If electrochemical sintering is used to fuse metal particles, then energy consumption is reduced, but conductivity is insufficient
Solution Approach 1:
The patent merges electrochemical sintering and photonic sintering into a hybrid process. The electrochemical step initiates particle fusion with low energy input, creating initial conductive pathways, while the subsequent photonic step enhances conductivity by providing controlled thermal energy to complete the sintering process and form robust metallic bonds.
Solution Approach 2:
The patent applies electrochemical sintering as a preliminary step before photonic sintering. This preliminary action reduces the energy barrier for subsequent photonic sintering by pre-fusing particles and removing oxide layers, thereby improving overall conductivity while reducing the total energy required compared to photonic sintering alone.
3Ease of manufacture
If drop casting is used to deposit metal particles, then manufacturing is simplified, but resolution deteriorates due to liquid spreading
Solution Approach 1:
The patent introduces a binder as an intermediary substance that controls the rheology and drying behavior of the metal particle suspension. The binder formulation manages liquid evaporation rates and capillary forces during drying, preventing uncontrolled spreading and maintaining pattern resolution while still allowing simple deposition methods like drop casting or inkjet printing.
4Reliability
If thick metal layers are deposited, then conductivity is improved, but substrate integrity is compromised
Solution Approach 1:
The patent applies local quality by creating non-uniform metal particle distributions with higher particle density and better packing at particle-particle contact points and lower density toward the substrate interface. This local optimization ensures high conductivity where needed (at particle contacts) while reducing overall layer thickness and stress on the substrate.
Solution Approach 2:
The patent creates a composite structure consisting of sintered metal particles with voids and pores, rather than dense bulk metal. This composite morphology achieves adequate conductivity through particle contact networks while using less material and reducing thermal and mechanical stress on the underlying substrate compared to thick continuous metal layers.
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 achieves high conductivity, durability, and flexibility in metal traces, suitable for biodegradable electronics, with reduced energy use and minimal substrate damage, enabling applications in transient devices like sensors and PCBs.
Implementation Method 1
removing an oxide layer around the particles is made by an electrochemical process in which use of a reducing agent is made
Implementation Method 2
sintering is a heat sintering induced by light
Implementation Method 3
heat sintering induced by light
Data Source
AI summary
It is disclosed a method for manufacturing an electrically conductive metal trace (1) comprising depositing metal micro or nano particles (2) in or on a substrate (3); removing an oxide layer (4) around the particles; sintering the particles after oxide layer removal to form the electrically conductive metal trace (1). The method is characterized in that the step of removing the oxide layer is an electrochemical process wherein the metal micro or nano particles are contacted by a reducing agent (5), and the step of sintering is heat sintering induced by light (6). The method is particularly suitable for manufacturing a transient electrically conductive metal trace.