The following is a detailed user guide for the nanolaser direct writing system, covering principles, operating procedures, and precautions:

1、 System Principles and Core Components

Nano laser direct writing technology directly writes micro nano structures on the surface of photosensitive materials through high-precision laser beams, without the need for traditional masks, and is suitable for fields such as flexible electronics and photonic devices. Its core includes:

-Light source system: UV/femtosecond lasers are commonly used, and shorter wavelengths can achieve smaller focused spots (such as 355nm UV lasers that can reach sub micron levels).

-Sports platform: Air floating guide rail+piezoelectric ceramic driver combination, achieving nanometer level positioning accuracy.

-Objective system: High numerical aperture (NA>0.8) objective compresses the spot size and increases energy density.

-Control system: The computer coordinates the laser pulse frequency, scanning speed, and platform movement, and supports importing Gerber/DFF files.

2、 Detailed explanation of the entire process operation

1. Pre preparation stage

-Substrate pretreatment: Silicon wafers need to be cleaned with Piranha solution to remove organic matter, and glass substrates need to be pre coated with thickening agents (such as HMDS) to enhance photoresist adhesion.

-Coating process: When spin coating photoresist (SU-8/PMMA), the speed gradient is set to low starting speed (500rpm/s to 3000rpm), and the thickness error is controlled within ± 5%. The soft drying process (90 ℃/2 min) eliminates solvent residue.

-Earthquake prevention measures: Start the isolation table, turn off the air conditioning vents, and stabilize the laboratory temperature and humidity below 22 ± 1 ℃/45% RH.

2. Key steps of exposure

-Focus calibration: Real time monitoring of the focal plane position using a laser interferometer, with an error of ≤± 0.1 μ m. The Z-axis fine adjustment step accuracy reaches 0.01 μ m.

-Dose optimization: Determine the optimal single pulse energy (typical value of μ J level) and repetition frequency (kHz level) through matrix experiments. For example, the commonly used dosage range for SU-8 photoresist is 10-50 mJ/cm ².

-Dynamic compensation: Enable automatic height tracking for curved substrates to maintain a constant working distance. When the tilt angle exceeds 5 °, the projection distortion needs to be corrected.

3. Development and post-processing

-Positive gel development: The soaking time of MF-319 developer solution depends on the thickness (about 60 seconds for a thickness of 1 μ m), gently shake to avoid peeling. Negative glue needs to be fixed with isopropanol.

-Hard baking curing: Step heating to 150 ℃ and maintaining for 30 minutes to crosslink the polymer network. Cooling rate ≤ 5 ℃/min to prevent cracking.

-Residual removal: Oxygen plasma ashing to remove adhesive residue, with parameters set to power of 80W, pressure of 50Pa, and duration of 120s.

3、 Daily maintenance standards

-Optical component maintenance: Use a dust-free cotton swab dipped in anhydrous ethanol to wipe the objective lens every month, and do not touch the coating layer. Testing accuracy every six months.

-Mechanical transmission lubrication: Regularly apply low-temperature grease (suitable for -40 ℃~+80 ℃) to the Y-axis guide rail to avoid grease contamination of the optical window.

-Software backup strategy: Export project files to a dedicated hard drive every week, and encrypt and archive important parameters. Be sure to uninstall the drivers before reinstalling the system.

-Security protection upgrade: Install an infrared sensing emergency stop button, and strictly control laser leakage within Class I safety standards.