Semi-Dry Polymer Patterning for Vertical-Sidewall Microstructures
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Solution Overview
Problem
Current printed electronics methods struggle with forming high-resolution patterns using materials like reactive metals and metal oxides due to issues such as rapid oxidation, high costs, and edge roughness, which limits their performance and scalability.
Innovation Solution
The method involves using a semi-dry polymer ink film with reverse-offset patterning to achieve vertical sidewalls, eliminating the need for adhesive layers and enabling the deposition of materials like aluminum and titanium, while combining with various deposition techniques for high-resolution patterns without edge ears.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional printing techniques (inkjet, screen, or gravure printing) are used to print resist layers, then the printing process is simple and cost-effective, but the resulting resist pattern has slanted sidewalls that cause edge ears of the deposited material
Solution Approach 1:
The invention changes the physical state parameter of the polymer ink from liquid to semi-dry film. This parameter change fundamentally alters the patterning mechanism: the semi-dry film can be mechanically fractured by a patterned roller to produce vertical sidewalls, whereas liquid ink cannot be fractured in the same manner and produces slanted sidewalls through wet chemical etching or lift-off processes
2Reliability
If nanoparticle-based conductor layers are printed using precious metals such as silver or gold, then high conductivity is achieved, but the manufacturing cost becomes significantly higher than the cost of the precious metal itself
Solution Approach 1:
The invention replaces expensive precious metal nanoparticle inks with inexpensive polymer-based resist materials. The polymer resist serves as a temporary sacrificial layer that is fractured and removed after enabling precise patterning of the conductive material, eliminating the need for costly precious metal inks while maintaining pattern precision
Solution Approach 2:
The polymer resist film acts as an intermediary material that enables precise patterning transfer. Instead of directly printing conductive nanoparticles which requires expensive materials and complex processes, the polymer resist serves as a mediator that can be precisely patterned through mechanical fracturing, then used to define the conductive layer pattern through vacuum deposition
3Adaptability or versatility
If printed patterning methods (lift-off or printed wet etching) are used to pattern vacuum-deposited layers, then the availability of printed materials is expanded, but edge ears and high line edge roughness are formed that limit the attainable linewidth resolution
Solution Approach 1:
The invention inverts the conventional patterning sequence: instead of printing the resist and then depositing material to be removed (lift-off), the method prints the resist, deposits the material, and then removes the resist. This inversion, combined with semi-dry film fracturing, produces vertical sidewalls that prevent edge ears and achieve high linewidth resolution
4Reliability
If reactive metals such as aluminum or titanium are formed as conductive inks, then low-work function and Ohmic contacts to n-type semiconductors are achieved, but rapid oxidation in air forms thin and dense oxide layers that prevent conductivity
Solution Approach 1:
The invention uses vacuum deposition to deposit reactive metals like aluminum and titanium in an inert vacuum environment, preventing oxidation during the patterning process. The polymer resist fracturing method enables precise patterning of these reactive metals without requiring them to be formed as oxidative-resistant nanoparticle inks, thus maintaining their excellent electrical properties
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 allows for low-cost, high-quality conductive structures with vertical sidewalls and uniform layer thickness, achieving resolutions down to 0.1 μm, matching the electrical characteristics of vacuum-processed films and enabling scalable, cost-effective production.
Implementation Method 1
the semi-dry polymer ink film is fractured by a patterned roller to produce vertical sidewalls
Implementation Method 2
the semi-dry polymer ink film is fractured by a patterned roller
Implementation Method 3
combining with various deposition techniques for high-resolution patterns
Data Source
AI summary
The present invention relates to a method and an apparatus for manufacturing of a desired pattern of an electrically conducting, semiconducting or insulating material on a substrate. A patterned polymer ink film (22′) is produced out of a semi-dry polymer ink by bringing a three-dimensional relief pattern with a positive image of the desired pattern (25) temporarily into contact with the semi-dry polymer ink film (22) so that portions (22″) of the semi-dry polymer ink film (22) are transferred to the three-dimensional relief pattern (25). The patterned polymer ink film with the negative of the desired pattern (22′) has vertical sidewalls caused by fracturing of the semi-dry polymer ink film (22) with cohesion by the edges of the three-dimensional relief pattern (25) and adhesion between the second portions (22″) of the semi-dry polymer ink film (22) and the three-dimensional relief pattern (25). The patterned polymer ink film (22′) is transferred onto a substrate (26), and a conductive, semi-conductive or insulating material layer (30′) is deposited onto the substrate (26) using physical vapor deposition or chemical vapor deposition. The patterned polymer ink film (22′) is dissolved from the substrate (26) with an organic solvent to yield the desired pattern (30).