Inkjet Printing Conductive Patterns Surface Modification Layer
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Solution Overview
Problem
Inkjet printing methods for forming conductive patterns on substrates often result in open-circuits or short-circuits due to differences in surface energies between the ink and the substrate, leading to bulging ink droplets and discontinuous patterns.
Innovation Solution
The method involves forming a first modification layer on the substrate using a surface modification ink that reduces the surface energy difference with the target ink, allowing for the distribution of conductive metal particles and preventing bulging, and optionally using a second modification layer on the mask to control ink spreading and prevent short-circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the surface tension of ink is increased, then ink droplets are better contained and short-circuits are reduced, but ink droplets bulge and open-circuits occur
Solution Approach 1:
A surface modification layer is introduced as an intermediary between the substrate and the target ink. This layer modifies the surface properties to reduce the surface energy difference, allowing the ink to spread properly without bulging while maintaining continuous wiring patterns without short-circuits or open-circuits.
Solution Approach 2:
The surface energy parameters of the substrate are changed by applying a surface modification layer. This alters the interaction between the ink and substrate, enabling proper ink spreading and droplet containment simultaneously, thus resolving the contradiction between wiring continuity and droplet shape.
2Stability of the object's composition
If the surface tension of ink is decreased, then ink droplets spread better and continuous patterns are formed, but ink droplets are not contained and short-circuits occur
Solution Approach 1:
The surface modification layer acts as a mediator that controls the spreading behavior of ink droplets. It allows sufficient spreading for pattern continuity while preventing excessive spreading that would cause short-circuits between neighboring wirings.
Solution Approach 2:
The surface modification is applied locally to specific regions where ink deposition is required. This creates localized zones with modified surface properties that control ink spreading precisely, ensuring pattern continuity in desired areas while maintaining isolation in other areas.
3Productivity
If larger ink droplets are used, then pattern formation speed is improved, but pattern thickness control becomes difficult
Solution Approach 1:
The surface modification layer serves as a controlled interface that receives larger ink droplets and distributes them uniformly. This allows the use of larger droplets for faster deposition while the modification layer ensures consistent thickness by controlling the spreading and absorption characteristics.
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 continuous formation of conductive patterns without open-circuits and reduces the risk of short-circuits, while also allowing for the rapid creation of thick conductive patterns with consistent thickness and width.
Implementation Method 1
a difference between surface energies of the surface modification ink and the substrate may be less than or equal to a difference between surface energies of the target ink and the substrate
Implementation Method 2
as a surface tension of ink increases, ink droplets ejected onto the substrate bulge
Implementation Method 3
forming a second modification layer that is phobic to the target ink on at least a surface of the mask
Data Source
AI summary
A method of forming patterns on a substrate, the method including: placing a mask having an opening defining a portion of one surface of a substrate on which patterns are to be formed on the substrate; forming a first modification layer in the opening by ejecting a surface modification ink onto a surface of the substrate through the opening; ejecting a target ink having droplets of sizes larger than those of a surface modification ink such that the target ink is distributed on the first modification layer in the opening; and removing the mask.