Femtosecond laser direct writing lithography
Principle:
Femtosecond laser direct writing lithography (FLDW) is a high-precision lithography method based on femtosecond laser technology. It uses the extremely short pulses and high peak power of femtosecond lasers to directly write patterns on the surface or inside of materials to achieve high-resolution micro-nano structures. The following is a detailed introduction to the basic principles, process flow, application scenarios, advantages and etching accuracy of femtosecond laser direct writing lithography:
The basic principle of femtosecond laser direct writing lithography relies on the extremely short pulses (usually on the order of 10^-15 seconds) and high peak power of femtosecond lasers, which makes the interaction between lasers and materials have unique characteristics:
1. Nonlinear absorption: The high peak power of femtosecond laser pulses causes nonlinear absorption effects in materials, such as multiphoton absorption or nonlinear ionization.
2. Ultrafast processing: The extremely short pulse width makes the heating and cooling process of materials very rapid, reducing thermal diffusion and thermal damage.
3. High-precision positioning: Through a high-precision three-dimensional scanning system, the laser can be accurately positioned and processed on the surface or inside of the material.
Processing capabilities:
Process flow:
1. Laser preparation: Select a suitable femtosecond laser and adjust laser parameters (such as wavelength, pulse width, power, etc.).
2. Sample preparation: Fix the material to be processed (such as glass, polymer, metal, etc.) on a three-dimensional scanning platform.
3. Laser direct writing: Control the scanning path of the laser beam through a computer and process directly on the material according to a predetermined pattern.
4. Pattern formation: The laser interacts with the material to form the required micro-nano structure on the surface or inside.
5. Post-processing: Perform subsequent processing such as cleaning, etching or coating as needed to enhance or improve structural performance.
Application scenarios:
Femtosecond laser direct writing lithography is widely used in the following fields:
Optoelectronic devices: Make photonic crystals, optical waveguides, integrated optical devices, etc.
Microelectromechanical systems (MEMS): Used to process micromechanical structures and microsensors.
Biomedical engineering: Make microfluidic chips, tissue engineering scaffolds and microneedles, etc.
Materials science: Study the microstructure and properties of new materials.
Nanotechnology: making nanowires, nanoholes and other nanostructures.
Advantages:
Ultra-high resolution: Femtosecond laser direct writing can achieve submicron or even nanometer resolution, which is suitable for making fine structures.
Material diversity: Able to process a variety of materials, including transparent and opaque materials.
Non-contact processing: The laser direct writing process is contactless, reducing mechanical stress and pollution.
Three-dimensional processing: Able to achieve free processing in three-dimensional space and make complex three-dimensional structures.
Low thermal damage: Ultrafast pulse width makes the material less affected by heat, reducing thermal damage and deformation.
Etching accuracy:
The etching accuracy of femtosecond laser direct writing lithography depends on the following factors:
Laser parameters: The wavelength, pulse width and power of the laser directly affect the resolution and accuracy of the processing. The short pulse width and high peak power of the femtosecond laser help to achieve high-precision etching.
Focus spot size: Using a microscope objective with a high numerical aperture can achieve a smaller focus spot size and improve resolution.
Scanning accuracy: The high-precision three-dimensional scanning platform ensures accurate positioning and movement of the laser beam and reduces processing errors.
Material properties: Different materials respond differently to femtosecond lasers. Selecting the right material and optimizing laser parameters can improve etching accuracy.
In general, femtosecond laser direct writing lithography is a high-precision, high-resolution micro-nano processing technology that is suitable for making complex micro-nano structures and has broad application prospects in optoelectronic devices, micro-electromechanical systems, biomedical engineering, and materials science.
OMeda (Shanghai Omedasemi Co.,Ltd) was founded in 2021 by 3 doctors with more than 10 years of experience in nanpfabrication. It currently has 15 employees and has rich experience in nanofabrication (coating, lithography, etching, two-photon printing, bonding) and other processes. We support nanofabrication of 4/6/8-inch wafers.
