Templated Polymer Microring Resonators with Residual-Free Thermal Reflow
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Solution Overview
Problem
Existing methods for fabricating high-quality factor microring resonators from polymers face challenges due to high costs, low throughput, and the need for expensive equipment and clean room environments, as well as issues with surface roughness and residual layers causing radiation loss.
Innovation Solution
A method using damascene soft nanoimprinting lithography (DsNIL) to pattern a cladding layer and backfill it with a high refractive index polymer, eliminating the need for expensive tools and clean rooms, and achieving a residual layer-free structure through thermal reflow to form a microring resonator with a quality factor greater than 1×105.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If standard fabrication methods (E-beam lithography, NIL) are used to achieve high Q-factor microring resonators, then manufacturing precision is improved, but device complexity and cost increase due to requiring expensive equipment and clean room environments
Solution Approach 1:
The patent changes the fabrication parameters by using solution-based polymer processing instead of traditional lithographic methods. This involves dissolving polymer materials in solvents to create spin-coatable solutions, then using thermal reflow processing instead of photolithography and etching, thereby simplifying the fabrication process while maintaining high Q-factor performance
Solution Approach 2:
The patent employs disposable polymer materials that can be easily processed and discarded, replacing expensive and complex inorganic materials and fabrication equipment. The use of solution-processable polymers allows for low-cost, high-throughput fabrication without requiring clean room environments or specialized lithography tools
2Productivity
If conventional NIL is used to fabricate polymer microring resonators, then productivity is improved through reduced fabrication time, but manufacturing precision deteriorates due to residual layers causing radiation loss
Solution Approach 1:
The patent utilizes phase transitions of polymer materials by dissolving them in solvents to form liquid solutions for spin coating, then using thermal reflow to induce phase separation and surface tension-driven self-organization. This process eliminates residual layers by allowing the polymer to reflow and self-smooth during the thermal processing stage, achieving both high productivity and high surface quality
3Manufacturing precision
If nanoscale feature sizes are required for high Q-factor resonators, then manufacturing precision is improved, but ease of manufacture deteriorates due to difficulty in controlling surface roughness and achieving uniform patterns
Solution Approach 1:
The patent employs self-service mechanisms where the polymer solution automatically self-organizes during spin coating and thermal reflow. Surface tension forces during thermal reflow cause the polymer to self-smooth and eliminate residual layers, while the spin coating process automatically achieves uniform thickness distribution. This self-organizing behavior simplifies fabrication by eliminating the need for complex lithographic patterning and precise etching controls
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 high-quality factor microring resonators with low defects, reduced radiation loss, and compatibility with various polymers and flexible substrates, facilitating high throughput fabrication without the need for specialized equipment.
Implementation Method 1
annealing for thermal reflow of the solid polymer in the at least one trench microfeature
Data Source
AI summary
Methods of making optic structures (e.g., microring resonator, meta-elements) include imprinting a first surface of a moldable polymer having at least one inverse micro/nano-feature into a second surface of a first polymeric cladding layer disposed on a second substrate to form at least one trench micro/nano-feature contrapositive to the at least one inverse micro/nano-feature. A liquid polymeric precursor is applied into the at least one trench micro/nano-feature where it is solidified to form a solid polymer. A difference between a first refractive index of the first cladding layer and a second refractive index of the solid polymer is ≥about 0.05. The solid is heated for thermal reflow to define a meniscus followed by applying a second polymeric cladding layer thereon. Organic cladded (e.g., microring resonator) optic structures are also provided, which may have a quality (Q)-factor of ≥about 5×105 around 770 nm wavelength).